Missouri's gun laws are now basically the same as Kansas', which I think was part of how they got through the Missouri legislature. Other states with essentially the same laws include Arizona, Wyoming, Alaska, and Vermont.
Besides, I'm not convinced that the new law is really going to change who is carrying. Our concealed carry law was pretty relaxed to begin with and a lot of people that I know have already gone through the CCW classes and gotten their permits. I almost never bother to carry, but that's mostly because the areas I'm generally in are pretty quiet in terms of crime.